diff --git a/linker/linker.h b/linker/linker.h
index 789640c..16c65a1 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -204,3 +204,5 @@
   size_t reserved_size = 0;
   bool must_use_address = false;
 };
+
+ElfW(Versym) find_verdef_version_index(const soinfo* si, const version_info* vi);